Is looking away from the fretboard something people give conscious thought to, or does that just come naturally in its time?
Saw some pictures of me back in the day, playing bass in a garage band, and my eyes were always glued to my left hand. Obviously not a hallmark of high-level playing.
Eric Johnson disagrees…obviously 
Personally, if I’m at a gig, some level of interaction between performer and audience makes such a difference. But if the on-stage antics/aesthetics are taking over the quality of the playing, then I would much prefer that the pay attention to what they are playing. I think it can also depends on the music. For example Joe Satriani is great at looking at the crowd and creates a great vibe - he has such a command over his playing. However, many moons ago I saw Tool live where they spent pretty much the while gig stationary position, making no real show of it - it was one of the best performances I have been to! The lack of visuals and the stellar sonic production had me almost hypnotized! Immersed completely in the music.